feat: add inline CI, review, and merge status to mergify stack list (#1117)

Enhances `mergify stack list` to show CI status, review status, and
merge conflict state for each PR in the stack.

- Default: summary line (CI: ✓ passing | Review: ✓ approved)
- --verbose: detailed check names and reviewer names
- --json: full structured data (ci_checks, reviews, mergeable)
- Conflict indicator (✗ conflicting) when PR has merge conflicts

Fetches check-runs and reviews in parallel with bounded concurrency.
Callers like `stack open` skip the extra fetches via include_status=False.


Claude-Session-Id: 2d9f4a52-4a1d-4a50-a459-3b57847dec9f

Author: jd

mergify_cli/github_types.py

@@ -20,6 +20,7 @@ class PullRequest(typing.TypedDict):
     node_id: str
     merged_at: str | None
     merge_commit_sha: str | None
+    mergeable: bool | None
 
 
 class Comment(typing.TypedDict):

mergify_cli/stack/cli.py

@@ -517,18 +517,26 @@ async def sync(
     is_flag=True,
     help="Output in JSON format for scripting",
 )
+@click.option(
+    "--verbose",
+    "-v",
+    is_flag=True,
+    help="Show detailed CI check names and reviewer names",
+)
 @utils.run_with_asyncio
 async def list_cmd(
     ctx: click.Context,
     *,
     trunk: tuple[str, str],
     output_json: bool,
+    verbose: bool,
 ) -> None:
     await stack_list_mod.stack_list(
         github_server=ctx.obj["github_server"],
         token=ctx.obj["token"],
         trunk=trunk,
         output_json=output_json,
+        verbose=verbose,
     )